We are seeking healthy adults, 55-90 years old for those with memory impairment or Alzheimer's disease and 65-90 years old for those without memory impairment, to participate in a research study. The goal of the study is to determine whether imaging of the brain (through MRI, PET and amyloid imaging scans) can help predict and monitor the onset and progression of Alzheimer's disease.

In addition to neuroimaging, the study will collect and test blood and cerebral spinal fluid to determine if biomarkers can predict and monitor the disease. Testing cerebral spinal fluid is the only way to obtain important brain information.

Participants will be asked questions about their memory and thinking and must have a friend or relative who can answer 30 minutes of questions about your day-to-day activities and accompany you to all clinic visits.

If you qualify, you will be asked to have 13 brain scans over the course of 54 months, follow-up memory and thinking testing as well as blood draws every 6 months after the initial visit for a period of 54 months. You will also be asked to have a lumbar puncture (spinal tap).

All evaluations will be free of cost and reimbursement for time and transportation will be up to $1750.

This is a Phase 3, safety and efficacy study of Dimebon for the treatment of Alzheimer's disease. Study participants are asked to come for study-related visits 10 times during a 1-year period, take study medications as directed by study personnel, and complete all study-related procedures.

ELIGIBILITY CRITERIA

Inclusion criteria:

1. Have mild to moderate Alzheimer's disease.

2. Be 50 years of age or older.

3. Have been taking Aricept (Donepezil) for at least 6 months.

4. Have a caregiver who assists (or directly supervises) the participant at least 5 days per week for at least 3 hours a day.

5. Living in the community and may be living in an assisted-care facility if living independently.

More information about the study may be found on the attached document.

We are now enrolling men and women, ages 45 to 90, with memory loss or mild cognitive impairment (MCI) to participate in this study. A study partner will also be needed to participate in this study. Volunteers may receive investigational medication, study-related medical care, laboratory testing and cognitive testing.